Clamp-joint



` Ai. EDQUIST.

CLAMP JOINT.

(No Model.)

- Patented Nov. 1o, 1896.

UNITED STATES ATENT OFFICE.

ANDREV EDQUIST, OF DENVER, COLORADO.

CLAM P-JOINT.

SPECIFICATION forming part of Letters Patent No. 571,042, dated November 10, 1896.

Application iiled May Z5, 1896. Serial No. 592,967. (No model.)

To all whom t may concern:

Beit known that I, ANDREW EDQUIs'r, a citizen of the United States of America, residing at Denver, in the county of Arapahoe and State of Colorado, have invented certain new and useful Improvements in Clamp-Joints; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same,

reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specication.

My invention relates to clamp-joints5 and it consists, primarily, in a clamping-bar having a suitably-threaded tightening-screw at one or both ends and at each end passing through an opening in a lune-shaped jaw provided with a corresponding female screw when required, the convex sides of said jaws being turned toward each other and having a curve of greater radius than the curve of the concave recesses in the wood in which they are placed.

In the drawings, Figure l is a plan view of a clamp-joint of the right-and-left-screw variety embodyingmy invention. Fig. 2 is a sectional view thereof on the line 2 2 of Fig. 1. Fig. 3 is a view showing a modification of the single-screw variety, and Fig. l is a perspective view of one of the clamping-jaws.

The letters a and a represent two luneshaped clamping-jaws, each having a central opening o for the passage of the ends of bar b, said opening being threaded conformably to the right-and-left screws s and s at either end of bar b, their convex sides turned toward each other when in place on bar b. Two

spurs c and c project from the lower edge of the convex surface of each jaw adjacent to the openin g o. One or both ends of bar b are flattened, or suitable holes are pierced at its middle for the operating-wrench. The modified form shown in Fig. 3 has screw s only, the other end of bar b passing loosely through an unthreaded opening in jaw d and being provided with a head h, .against which the concave side of jaw a plays.

In operation circular recesses d and d are made in the boards w and w to be joined, connected by the channel e, the curve of said recesses being of less radius than the curve of the convex surface of the clamping-jaw. The clamp is then placed in the recesses thus formed and suitably tightened by the Wrench. As they tighten, the jaws begin to draw first at their extremities, and when tightened to their limit the strain will be equally distributed over their convex surface. In tightening, the spurs enter the wood and hold the clamp in place in the event of shrinkage.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is-

The combination of a joint clamp and holder having convex jaws and means for drawing the jaws together with the boards to be joined having concave recesses adapted to receive the jaws, the curve of the recesses being of less radius than the curve of stantially as described.

InV testimony whereof I affix my signature in the presence of two witnesses.

ANDREW EDQUIST.

the jaws, sub- VVitnesses GEORGE Errrcn, FRANK DoBBERsTEIN. 

